Proof that having the sighted revision as the standard
view (which you
have to for it to be meaningfully useful) doesn't result in a drop in
editing rate.
Proof that en would be able to keep up with the required rate of
sighting (We have a hard time marking new pages as patrolled at the
moment)
If you want to use drug articles as the foundation for your argument
proof that it would provide any protection against subtle vandalism.
There is only one way to prove any of that, though, and that's giving
it a go. If we only make the flagged rev the default version for
articles that are currently (semi-)protected keeping up with the
sighting would be easy - that's the version of the proposal that
should be completely uncontroversial.